"He really is dead to me." Cassandra Thorburn's bracingly honest words on her divorce.

We’ve not seen much of Cassandra Thorburn since her husband of 21 years Karl Stefanovic left her and their three children – aged 18, 12, and 10 – in September last year.

The paparazzi were desperate for her immediate reaction, of course. And we saw her picture splashed across tabloids cutting a tired figure with dark sunglasses moving belongings out of the family home.

But Cassandra, 46, remained quiet in the storm of speculation and judgment that followed the split. She said nothing when news broke that Karl, 43, had started dating fashion designer Jasmine Yarbrough, 33.

She’s been careful and understandably withdrawn, until now.

Speaking to Woman’s Day in her first interview about their marriage breakdown, Cassandra – a former journalist – said she was “completely gazumped” when she realised Karl had gone.

“There were days in the beginning I would get up, put on a brave face and drop the kids at school, then I’d get to the back door and I would lie in a heap for the rest of the day unable to move,” she told Woman’s Day.

“There were very dark days.”

Usually, the stories we hear about divorce are ones of transformation. Of trauma leading into a second life; a different type of success; a newfound happiness.

Certainly, this is true for Cassandra (more on that later) but her honesty when discussing the awfulness of the separation is refreshingly real. People around Australia will be nodding their heads, thinking: "yes, I felt this, too".

"I questioned and doubted myself about everything," she said. "I slept on the couch in front of the fire for months because I didn’t want to go near the marital bed. I was in a very dark place."

"I realised I was going through stages of grief, and to me it was like someone had died."

Cassandra also doesn't feel the need to portray her relationship with her now ex-husband as anything other than what it is.

There is no pretense of amicability or "conscious uncoupling". There is only the mess and wretchedness that comes with untangling a life of 21 years amidst hurt and anger and disbelief.

"The children still have a father but I don’t have a husband," she told Woman's Day. "He really is dead to me and no, we won’t ever be friends again."

But the 'transformation' did come. Cassandra dragged herself out of her depression and has just completed her first children's book.

"I get up every day with only one purpose – to make sure my three beautiful kids are happy – everything else really doesn’t matter," she told Woman's Day.

"I’m only concentrating on being strong in every way, and being the best mum I can be."

Mamamia Out Loud discusses Karl Stefanovic and Cassandra Thorburn’s divorce. Post continues below.